1. Field of the Invention
This invention relates to a milk-extraction device with a drive motor and a vacuum generation unit having a vacuum-generating device, a change-over unit attached thereto, which determines the extraction cycles by a rotatingly driven change-over member, and at least one extraction attachment which is or can be brought into a flow connection with it and has a suction funnel, which can be applied to a breast, and a milk receptacle.
2. Discussion of Related Art
A milk-extraction device for human breast milk is disclosed in German Patent Reference DE 102 28 455 B4. In this known milk-extraction device a vacuum generation unit, having a vacuum source or vacuum unit driven by a motor, is connected via a change-over unit, which has a rotating valve and determines the suction cycle to an extraction attachment which has a suction funnel for placement against the breast. For receiving the extracted milk, is a milk receptacle, wherein the milk reaches the latter, secure against flow-back, via a valve arranged at the receptacle opening. For a connection with the vacuum-generation unit on the one hand, and the extraction attachment on the other, openings are in the change-over unit which, for the cyclic generation of the vacuum by rotating channels, can be brought into a flow connection with each other in a rotating change-over member. Also, openings are in the change-over unit which, during the rotation of the change-over unit and the connecting channels contained therein, make a cyclic connection between the extraction attachment and the pressure side of the vacuum unit between the suction phases, so that the extraction effect at the breast is aided, and the actuation of the receptacle valve operates dependably. A cyclical connection with the exterior atmosphere, also provided via the rotating channels, is at a further opening of the change-over unit by an outlet line with a ventilation section and a muffler arranged thereon. Reference is made to the mentioned publication regarding further details of this milk-extraction device, in which regulating possibilities regarding the cycle and/or the strength of the vacuum are also listed. The change-over unit with the rotating valve has proven itself in actual use. However, possibilities still exist for further optimization regarding operation, control and construction.
German Patent Reference DE 10 2004 030 692 B3 discloses a milk-extraction device with two suction attachments, which can be connected to a pump unit 10, wherein a vacuum-generation unit and a change-over unit in accordance with the previously mentioned publication can be contained in the pump unit.
Further milk-extraction devices are shown in German Patent Reference DE 37 38 282 C2, in which a pulsing device is provided for affecting the suction cycle, and U.S. Pat. No. 6,090,065, in which a vacuum-generation device with diaphragm elements arranged in a special way and channel arrangements are provided.
A further milk-extraction device is shown in German Patent Reference DE 38 20 211 C2, in which a fluid-collecting vessel is connected via a valve arrangement with a vacuum source or with the atmosphere, and a cyclical change between suction and airing phases is controlled by a timed switching arrangement. A valve arrangement is actuated by a magnetic coil.